214 MK. C. T. TEECHMANN ON A MASS OE ANHYDRITE [June I913, 



I am told that when the stratified beds at the top of the Lower 

 Limestones were encountered beneath the Shell-Limestone, the dip 

 was found to be due south, at an angle of 16°; and that, in con- 

 sequence, these beds occurred 50 feet lower in the southern than in 

 the northern shaft. However, when the Marl Slate was reached in 

 the former shaft, the dip was a very slight one to .the south-east, 

 whence we may infer that the disturbance of the upper part of the 

 Lower Limestone was a local phenomenon. 



In the drift, 210 feet east of the shafts, beneath the Boulder 

 ■Clay, an incoherent, soft, yellow limestone of marly appearance, 

 showing no stratification, was encountered, and pierced to a depth 

 of 246 feet. It exhibits a distinct ' roestone' structure in samples 

 which I obtained. The best explanation that I can offer of this 

 sudden change is that here we are off the reef of Shell-Limestone, 

 and that this substance is part of the collapsed Upper Limestones 

 occupying the eastern slope of the reef. 



VII. Notes on the Paleontology of the Haetlepool Abea. 



The changed conditions represented by the Middle Limestones in 

 the Durham area, while introducing at least thirty new species, 

 gave the Lower Limestone fauna, so to speak, a new lease of 

 life under the protection of the Shell-Limestone bryozoonal reefs. 

 There is evidence to show that this sudden influx was never 

 repeated, but that the fauna was caught and trapped in a sea 

 isolated from the oceans. Its adverse fortunes and gradual de- 

 cadence and extinction, following on the slow failure of the 

 conditions which inaugurated it, can be studied as we ascend in 

 the Shell-Limestones. 



Obviously, then, new species are hardly to be expected in the 

 Upper Shell-Limestones, more especially as the material for the 

 classical monographs was chiefly obtained from the highly fossil- 

 iferous localities of the main Shell-Limestone then open in the 

 Sunderland area. Nevertheless, many of the typical forms described 

 by King and others undergo considerable change as we ascend in 

 the formation. 



Owing to the continued absence of a revision of the Anglo- 

 German Permian fauna in the light of recently investigated marine 

 Permian faunas, the lists of fossils are somewhat unsatisfactory. 



To avoid any confusion, I have based my identifications for all 

 forms, except the brachiopoda, on King's Permian Monograph 

 (1850). For the brachiopoda I have made use of Davidson's 

 ' Monograph of British Permian Brachiopoda ' (1857-62). 



